I would NOT use Grace for a boy even in the middle. Even though it is technically, a neutral (non-gendered) noun, it IS a common girls' name. A boy with the middle name Grace will almost surely be embarrassed of the name. I recommend giving your son a full name he will feel good about.

Mother of three teenagers: (1) Daniel Glen, (2) Timothy Austin, and (3) Rebecca Jane. All middle names honor family, with Jane used three generations in a row. (A second girl would have been Susanna Eve).

I would assume Saffron is a girls name. ArcherGrace as a boys name has less potential for teasing in that he would mostly go by Archer, but Grace is such a girl's name that you'd have to explain it in that context of why you gave him such a middle name. I think it unlikely he would get through school without it coming out, or family saying something etc.

Chelsea
- Named after the place. A guy named Chelsea, who through his name became fascinated with names.

There is an author named JonathanSaffron Foer (Everything is Illuminated), and its the only thing I can think of that shows it could work on a boy. I would still probably use it for the middle name though.